Slot pyrolysis reactor and method of pyrolysis

ABSTRACT

Apparatus for conducting the flash pyrolysis of a primary material, particularly coal, and employing a secondary material, particularly hot char, as a heat source, comprising a rectangular slot for injection of a stream of particulate coal, which communicates with a substantially rectangular reactor or pyrolysis chamber. Wells are positioned on opposite sides of the pyrolysis chamber and in communication therewith, for introduction of fluidized secondary material, particularly hot char, into the pyrolysis chamber for admixture therein with and for heating the stream of primary material, such as coal. The pyrolysis chamber has a transition chamber, and a cylindrical separator chamber communicates with the transition chamber for receiving pyrolysis products. The separator chamber is provided with a tangential inlet, a solids outlet conduit positioned about 90° around the circumference of the separator chamber from the tangential inlet, and a perforate gas receiver. The process for flash pyrolysis of a particulate primary material, such as coal, utilizing apparatus as described above.

This is a continuation of application Ser. No. 699,995, filed June 25,1976, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to apparatus and a method for pyrolysis ofa primary material, such as coal, preferably utilizing a second materialsuch as hot char as a heat source, and more particularly is directed toapparatus for flash pyrolysis of particulate coal, and utilizingparticulate hot char, employing components having a geometry or shapewhich affords simpler and more feasible "scaling up" of the apparatusdesign for commercial application, and which also provides additionaladvantages.

For a process that is essentially plug flow in nature, that is, whereinthe reactor components are mixed in a pyrolysis chamber in a radialrather than in an axial direction, and the resulting mixture has uniformcomposition and properties at any cross section of the reactor,selection of the geometry of the apparatus is not critical for purposesof "scaling up" for commercial application. For example, if theresidence time of the materials in a pyrolysis reactor is a function ofthe length of the reactor, throughput is increased by increasing thecross section of the reactor. Thus, in the period of time between rapidheating, that is mixing of the particulate materials in the reactor andsolids separation, the selection of a particular geometry for thereactor cross-section is relatively unimportant. However, the rapidheating and solids separation operations, are not plug flow in nature.

If a circular geometry is selected for the cross section of the reactor,a reactor design could be selected of the type disclosed and claimed inmy application Ser. No. 633,898, filed Nov. 20, 1975, which is acontinuation of Ser. No. 449,073 filed Mar. 7, 1974, now abandoned, inthe form of a coaxial jet mixer for mixing and pyrolysis of a primarymaterial source such as particulate coal, utilizing a secondary materialsuch as particulate char as a heat source, a tubular reactor and aconventional cyclone receiver. In an apparatus of this type a coalstream is introduced through an inlet such as a nozzle into a fluidizedannular stream of char, and the turbulent mixture pyrolyzed in thetubular pyrolysis reactor. As such design is scaled up to higherthroughputs, the mixing time is increased and the separation time in thecyclone is increased. Although this can be compensated to some degree bypermitting multiple injection systems and multiple cyclones orcollectors, the benefits of this additional apparatus is marginal andthe overall symmetry is disrupted.

It is an object of the present invention to provide a novel apparatusand method for pyrolysis of particulate materials, such as coal.

A further object of the present invention is to provide apparatus and amethod of such type which involves the use of non-circular ornon-tubular material feeding and pyrolysis reactor components.

A still further object of the present invention is to provide apparatusand a method of the above type employing a novel pyrolysis productsseparator design providing rapid separation of solids from gases, andincorporating means in such separator for collecting and withdrawingpyrolysis gases.

SUMMARY OF THE INVENTION

The present invention affords a simpler, more direct and practicalsolution to the problem of "scaling up" a pyrolysis reactor design whileinsuring that the residence times chosen for the mixing and rapidheating of the pyrolysis reactants, and the separation operationsfollowing pyrolysis, are at the optimum for the commercial design.

According to the invention, there is provided the concept of rectangularslot injection of the primary material which is to be pyrolyzed, such asparticulate coal, and mixing thereof with the secondary material servingas heat source such as fluidized char, resulting in a substantiallyrectangular geometry for the pyrolysis reactor. Thus, according to theinvention concept, a high velocity slot jet or slot stream ofparticulate coal, by which is meant a stream having a rectangular crosssection in a horizontal plane, is injected into a rectangular reactor.Such slot can be continuous in phase or it may be formed from a numberof circular ducts positioned to approximate the geometry of a slot. Oncean optimum slot width has been chosen, "scale up" can be accomplishedsimply by expanding the feed slot length or by stacking a plurality ofslot pyrolysis reactors or modules, according to the invention, inparallel.

The secondary material, such as particulate char, used as a heat sourcefor pyrolysis of the coal, is introduced into wells, particularly a pairof wells positioned on either side of the substantially rectangularreactor, wherein the char is fluidized, and the fluidized char is causedto overflow the wells into a mixing zone, wherein the turbulent slot jetor sheet stream of particulate coal, is mixed with the fluidized char.The resulting jet stream of particulate coal and entrained particulatechar is conveyed downwardly through the rectangular reactor forpyrolysis therein, the reactor terminating preferably in a rectangulartransition member to decrease the rectangular cross section of thestream of pyrolysis products and reduce the volume thereof, to therebyfacilitate introduction of the pyrolysis products into the separator.The mixture of pyrolysis products passing into the separator thus hasincreased velocity due to reduction in volume thereof as noted above.

The separator is of cylindrical design and has as an essential feature atangential inlet for introduction of pyrolysis products, such inletcommunicating with the above noted transition member, a tangentiallydisposed solids outlet conduit from the separator, and a porous orperforated gas receiver member mounted within the separator. In apreferred embodiment, the solids outlet conduit is positioned not morethan about 180° around the circumference of the separator from thetangential inlet so that the solid pyrolysis products or char solids,following introduction into the separator from the tangential inlet,preferably are caused to travel not more than half the circumference ofthe separator, most desirably about one fourth of the circumference ofthe separator, before impacting the wall of the solids receiver oroutlet conduit and being removed from the separator. Pyrolysis gases arewithdrawn from one or both ends of the perforated gas receiver, which ispreferably in the form of a perforated tube axially within theseparator. This separator design results in reduced residence time ofthe solids and gases in the separator, and more rapid separation than inconventional cyclones, minimizing contact of gases with solids andminimizing the time the gases are held at elevated temperatures beforequenching.

A number of variations of the basic reactor design described above canbe provided to accomplish the desired results. Thus, for example aplurality of such rectangular reactors including the slotted feed memberand cylindrical separator, can be stacked in parallel with thefluidization wells for the char each serving adjacent pairs of reactors.Further, each of the separators can be provided with opposed tangentialinlets to serve a pair of reactors. Also, the porous gas receiver can bedesigned to act catalytically on the volatiles stream.

THE DRAWINGS

The above and other features and advantages of the invention will bemore clearly understood by reference to the following detaileddescription of the invention, taken in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a preferred embodiment of pyrolysisreactor design according to the invention;

FIG. 1a is a view in elevation of the reactor design of FIG. 1;

FIG. 2 is a longitudinal section through the pyrolysis reactor of FIG.1;

FIG. 3 is a modification of the invention apparatus, showing a pair ofreactor modules stacked in parallel with opposed tangential inlets to asingle separator;

FIG. 4 is a modification similar to that of FIG. 3, but wherein one ofthe fluid-bed wells for the fluidized char serves two reactors;

FIG. 5 is still another modification of the invention, employing aplurality of stacked parallel reactors each having its own feed slot forprimary material such as particulate coal, and its own separator, butwherein the wells for the fluidized secondary material such as charserve adjacent reactors;

FIG. 6 illustrates formation of the feed slot from a number of circularducts positioned together to approximate the geometry of a feed slot;

FIG. 7 illustrates a modified form of slot for feeding the primarymaterial, that is a particulate coal stream, to the reactor; and

FIG. 8 is a view similar to FIG. 1a, and showing a further modification.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1, 1a and 2, numeral 10 designates a preferred formof slot reactor according to the invention.

The feed slot of the slot reactor 10 comprises a hollow rectangularmember 12 formed of a pair of parallel sides 14 and parallel end members16, providing a slot 18 of rectangular cross section from the top to thebottom of member 12.

The rectangular member 12 forming the slot 18 is vertically mounted on apyrolysis reactor 20, also of rectangular shape and having parallelsides 22 and parallel end walls 24. The length of the pyrolysis reactorcross section, as best seen in FIGS. 1 and 1a, between end walls 24, isgreater than the length of member 12 between end members 16, and of slot18, and the width of the reactor cross section is greater than the widthof the member 12 and of slot 18 therein. The lower portion 26 ofrectangular member 12 and the slot 18 thereof extends into the upper endportion of the reactor 20.

A pair of rectangular shaped wells 28 are mounted on either side of theupper end portion of the pyrolysis reactor, and extend from one end wall24 of the pyrolysis reactor to the opposite end wall 24 thereof. Each ofthese walls is provided with a horizontal grid or perforated plate 30mounted across and spaced from the bottom 32 of the well, and a gasinlet 34 is provided to the chamber 36 formed in the bottom of the wellbelow the plate or grid 30. A vertical stand pipe 38 is mounted in eachof the wells 28 and terminates at its lower end a short distance abovethe grid 30. The upper ends 40 of the sides 22 of the reactor 20,forming the inner walls of the wells 28, terminate below the top 42 ofthe reactor, leaving a slot 43 above the upper ends 40 of reactor sides22 for communication between the wells 28 and the space in the upperportion of the reactor between the upper end portions of reactor sides22 and the lower depending end portion 26 of the member 12, for apurpose described more fully hereinafter.

The rectangular reactor has a downwardly tapered transition portion 44which terminates in a rectangular slot 45 of substantially reduced crosssection as compared to the cross section of the reactor 20. An inletpipe 46 from the transition portion 44 facilitates introduction ofpyrolysis products into a separator 48. The separator 48 is in the formof a horizontally disposed tube or cylinder having an axial length equalto the horizontal length of the members 44 and 46.

Members 12, 20, 28, 44 and 46 have been designated as being rectangular,by which is meant that such components have a rectangular cross sectionin a horizontal plane.

The separator 48 has a feature thereof a tangential rectangular inlet 50from the inlet pipe 46, which extends substantially the entire length ofthe separator, and is of the same length as the slot 45. A solids outletduct 52 is connected to the lower portion of the separator 48 andextends tangentially downwardly therefrom, it being noted that the inlet54 to the duct 52 is tangentially disposed with respect to thecylindrical separator 48, opposite inlet 50, and extendscircumferentially around the separator 48 from a position extending from90° to 180° from the position of the tangential inlet 50 to theseparator. The positioning of the tangential inlet 50 to the separatorand the inlet 54 from the separator to duct 52 are for purposes notedhereinafter. The separator 48 also is provided with an axiallypositioned porous or perforated cylindrical gas receiver 56 for removalof gases from opposite ends thereof.

The solids outlet duct 52 communicates with a downwardly tapered chamber58 which in turn communicates with a solids collecting chamber 60.

In operation, a primary material such as particulate coal in a suitablecarrier gas such as an inert gas e.g. nitrogen, or hot recycle gas,methane or carbon monoxide, and substantially free of molecular oxygen,is injected as a high velocity stream, and generally having a Reynoldsnumber greater than about 2,000, through the slot 12 and into the upperportion of the rectangular reactor 20. A secondary material such as hotparticulate recycled char at high temperatures is fed from the inlet orstand pipes 38 of each of the wells 28 into a fluidization chamber 62.The char is rendered fluid by a suitable fluidizing gas, e.g. nitrogenor hot recycle gas, introduced at 34 and which passes through the gridor plate 30 into the fluidization chamber 62, such gas flow being chosenso as to fluidize the char. The fluidized char is caused to dischargeuniformly over the top edge or weir 40 from each of the wells 28 intothe rectangular reactor between the sides 22 thereof and the lowerportion 26 of the rectangular slot chamber 12. Once inside the reactor,the fluidized char soon falls into the path of the turbulent slot jet ofthe coal stream discharging from the lower portion 26 of the slotchamber 12. The coal slot jet is introduced rapidly enough into thereactor to form a jet stream which acts upon the char stream andentrains the particulate char, with complete mixing of the coal and chara short distance inside the reactor. The resulting turbulent jet streamof particulate coal and entrained particulate char expands as indicatedby the dotted lines 64 as it passes downwardly through the pyrolysischamber.

The mixed components of the pyrolysis reaction are conveyed downwardlythrough the rectangular reactor 20 and the transition chamber 44therefrom. When the pyrolysis products pass through the slot 45 intoinlet pipe 46, the velocity of the mixture is substantially increasedwhile the volume of the mixture is substantially reduced, due to thesubstantially reduced rectangular cross section of slot 45 as comparedto the rectangular cross section of the reactor 20. The mixture ofpyrolysis components then passes via inlet pipe 46 and the tangentialinlet 50 into the separator 48, the tangential introduction of thepyrolysis or char solids into separator 48 causing a swirling motion ofsuch solids around a portion of the inner periphery of the cylindricalseparator. Such char solids are caused to travel one quarter thecircumference of the separator or collector 48, as indicated at 66. Whenthe solids reach the near end 67 of the inlet 54 to the duct 52, thesolids are propelled tangentially along the dotted line 69 beforeimpacting the outer wall 68 of the solids outlet duct 52, and beingremoved via outlet conduit 52 and chamber 58 to solids collectingchamber 60. The pyrolysis gases pass through the perforated gas receiver56 and are withdrawn from the ends thereof.

The above described design of the separator 48 and the tangentiallocation of the inlet 50 and the location of the inlet 54 from theseparator to outlet duct 52 provide certain important advantages. It isknown to be preferable for improved yields of products, to separategases from solids in the mixture of the pyrolysis products as soon aspossible in order to minimize contact of gases with solids and also tominimize the time that the gases are held at elevated temperature priorto quenching. It is thus seen that in the above separator design, thesolids are only maintained in contact with the gases in the separatorduring the very short period that the solids travel over only onequarter the circumference of the separator until reaching the inlet 54to the outlet conduit 52, and are then removed from the separator. Thisis contrary to conventional cyclone operation wherein the solids aremaintained in contact with the cyclone wall for several revolutions ofthe cyclone circumference. Also, the gases remain at the elevatedtemperature in the separator for only a very short period before beingwithdrawn therefrom through the gas receiver 56.

The separated char solids removed from the solids collecting chamber 60or a portion of such solids can be recycled to the wells 28 forfluidization therein, as described above.

A number of variations of the apparatus described above and illustratedin FIG. 1 can be provided utilizing the basic invention principles.Thus, a plurality of reactors can be stacked in parallel with opposedtangential inlets to serve a pair of reactors. Referring to FIG. 3, apair of slot pyrolysis reactors 20 and associated components, of thetype illustrated in FIG. 1, are arranged in parallel side-by-siderelation, with the opposed tangential inlets 50 of the two reactorsbeing connected to the separator 48 at opposed 180° positions around thecircumference of the reactor, the solids outlet duct 52' in thisembodiment, however, being positioned at the lower end of the separator48 equidistantly around the circumference of the separator from each ofthe inlets 50.

A system similar to that of FIG. 3 is shown in FIG. 4, but wherein thecentral fluidization well 28' serves the adjacent pair of reactors 20.

In the embodiment shown in FIG. 5, three reactors 20 and associatedcomponents are stacked in parallel, with the intermediate wells 28aserving adjacent pairs of reactors, and wherein each of the reactorsdischarges into its own separator 48.

Referring to FIG. 6, there is shown a modification of the slot chamber12 of FIG. 1, and wherein an essentially rectangular slot 70 is formedfrom a number of essentially circular ducts 72 disposed in adjacentside-by-side contacting relation. The stream of particulate coal is fedsimultaneously into one end of each of the ducts 72, and the resultingstreams discharged from the opposite ends of the ducts 72 into thereactor merge together to form a stream of substantially rectangularcross section.

Although in the preferred embodiment of the invention apparatus asillustrated in FIGS. 1, 1a and 2, the lower discharge end of the slotchamber 12 has the same rectangular geometry slot configuration as therectangular slot inlet at the top of the slot chamber, in FIG. 7 thereis shown a modification of slot chamber 74, wherein the lower dischargeend 76 is constricted in the form of a rectangular nozzle to form a slotjet or stream having a narrower slot, that is, of smaller rectangularcross section, as compared to the slot jet at the top 78 of the jetchamber. In this embodiment it will be noted that the slot stream ofparticulate matter, e.g. coal, is further accelerated as it passesthrough the nozzle 76 and into the pyrolysis reactor.

In FIG. 8, there is shown a modification of the apparatus of FIGS. 1 and1a, wherein the transition chamber 44 is tapered inwardly as at 79 sothat the length of the slot 45, inlet 50, the separator 48 and theoutlet conduit 52 are all the same, but shorter in length than thereactor 20.

It will be understood that the primary material forming the slot jet canbe any particulate material which can be pyrolyzed in the pyrolysisreactor. In preferred practice such primary materials are coal, whichcan be bituminous or sub-bituminous coals of lignite.

The secondary material for heating the primary material such as coal toa suitable temperature in the pyrolysis reactor is preferably char,particularly recycled char, but can be other materials such as hotparticulate inert solids.

From the foregoing, it is seen that the invention provides a novelapparatus and method employing the principle of a slot jet reactorhaving increased efficiency and capable of producing high yields ofproducts, and which permits simple and practical scaling up forcommercial application once an optimum slot length has been selected, byextending the slot length or by stacking a plurality of slot pyrolysisreactors in parallel, as described.

While I have described particular embodiments of my invention forpurposes of illustration, it is understood that other modifications andvariations will occur to those skilled in the art, and the inventionaccordingly is not to be taken as limited except by the scope of theappended claims.

What is claimed is:
 1. Pyrolysis unit comprising means forming arectangular slot for formation of a slot stream of a particulate primarymaterial to be pyrolyzed, a substantially rectangular pyrolysis reactor,said slot communicating with said reactor, means positioned on oppositesides of said reactor and in communication therewith, for introductionof particulate secondary material as heat source, from said lastmentioned means to said reactor for admixture therein with said slotstream of particulate primary material, a substantially cylindricalseparator, means forming a transition chamber from said reactor, saidtransition chamber terminating in a rectangular slot, a tangential inletto said separator and in communication with said last mentioned slot andsaid transition chamber, a solids outlet conduit positioned not morethan about 180° around the circumference of said cylindrical separatorfrom said tangential inlet, and a perforate gas receiver mounted in saidseparator.
 2. Apparatus as defined in claim 1, said first mentionedmeans being a pair of rectangular wells positioned along opposite sidesof the upper portion of said reactor, said wells each comprising pipemeans for introducing said particulate secondary material to said well,a fluidizing chamber and means for introducing a fluidizing gas intosaid fluidizing chamber, and means to permit the fluidized secondarymaterial to overflow from each of said wells into the upper portion ofsaid reactor.
 3. Apparatus as defined in claim 2, said reactor having anupper wall portion terminating below the top of said reactor, said lastmentioned means comprising said upper wall portion and forming anoverflow weir from each of said wells into said pyrolysis reactor. 4.Apparatus as defined in claim 1, said solids outlet conduit beingpositioned about 90° around the circumference of said cylindricalseparator from said tangential inlet, said outlet conduit having a wallat the upper end thereof communicating with said separator, wherebysolids injected from said tangential inlet into said separator travelaround one quarter of the circumference of said separator beforeimpacting said wall of said outlet conduit for removal therein. 5.Apparatus as defined in claim 1, said perforate gas receiver comprisinga porous or perforated tube, said tube being mounted axially within saidseparator, and permitting removal of gases from an end of said tube. 6.Apparatus as defined in claim 1, said cylindrical separator beingdisposed with its axis in a horizontal position and having a lengthequal to horizontal length of said reactor.
 7. Apparatus as defined inclaim 1, said cylindrical separator being disposed with its axis in ahorizontal position and having a length smaller than the horizontallength of said reactor.
 8. Apparatus as defined in claim 1, said meansforming said rectangular slot being comprised of a plurality of circularducts positioned in side-by-side contacting relation.
 9. Apparatus asdefined in claim 2, including a plurality of said pyrolysis unitspositioned in parallel relation, and wherein those wells positionedbetween adjacent said units are in operative association with reactorsof adjacent units.
 10. Apparatus as defined in claim 2, including a pairof said pyrolysis units positioned in parallel relation, but employing asingle said separator, said tangential inlets from each of said unitsbeing in opposed 180° positions around the circumference of saidseparator.
 11. Apparatus as defined in claim 10, wherein those wellspositioned between a pair of said units are in operative associationwith each of the reactors of said units.
 12. Pyrolysis apparatus whichcomprises means forming a downwardly extending rectangular slot forformation of a slot stream of particulate coal to be pyrolyzed, asubstantially rectangular pyrolysis reactor, said slot communicatingwith the upper end portion of said reactor, a pair of rectangular wellspositioned along opposite sides of the upper portion of said reactor,said wells each comprising pipe means for introducing particulate charas heat source to said well, a fluidizing chamber and means forintroducing a fluidizing gas to said fluidizing chamber, and means topermit the fluidized char to overflow from each of said wells into theupper portion of said reactor, for admixture therein with said slotstream of particulate coal, a transition chamber depending from thelower end of said rectangular reactor, said transition chamberterminating in a rectangular slot of smaller rectangular cross sectionthan said rectangular reactor, a substantially cylindrical separatordisposed with its axis in a horizontal position, a tangential inlet tosaid separator, a rectangular inlet conduit communicating said lastmentioned slot with said tangential inlet to said separator, said lastmentioned inlet being of the same length as said last mentioned slot, asolids outlet conduit positioned about 90° around the circumference ofsaid cylindrical separator from said tangential inlet, and dependingfrom said separator, said outlet conduit having a wall at the upper endthereof communicating with said separator, whereby solids injected fromsaid tangential inlet into said separator travel around one quarter ofthe circumference of said separator before impacting said wall of saidoutlet conduit for removal therein, and a perforate tubular gas receivermounted axially in said separator, for removal of the gases from an endthereof.
 13. Apparatus as defined in claim 12, said cylindricalseparator having a length equal to the horizontal length of saidreactor, of said transition chamber and of said rectangular inletconduit.
 14. Apparatus as defined in claim 13, wherein said outletconduit communicates with said separator through an opening in saidseparator at the upper end of said outlet conduit.
 15. A pyrolysisprocess which comprises passing a high velocity stream of a particulateprimary material to be pyrolyzed through a rectangular slot to form ahigh velocity slot jet of said particulate material having a rectangularcross section, injecting said slot jet into a substantially rectangularpyrolysis zone, introducing a fluidized particulate secondary materialas heat source into said pyrolysis zone and mixing said particulateprimary material and said particulate secondary material in saidpyrolysis zone, and passing the resulting stream of said mixedparticulate primary and secondary materials through said pyrolysis zoneand pyrolyzing said mixture therein, passing the resulting stream ofpyrolysis products through a chamber having a rectangular cross sectionwhich reduces in size in the direction of flow, introducing said streamof pyrolysis products tangentially into a cylindrical separator zone,removing solids from said separator zone after said stream has passedaround only a fraction of the circumference of said separator zone andremoving gases from said separator zone.
 16. The process as defined inclaim 15, wherein said fluidized particulate secondary materialoverflows into said pyrolysis zone from wells on both sides of saidrectangular pyrolysis zone.
 17. The process as defined in claim 15, saidsolids being removed from an outlet conduit communicating with saidseparator zone at a location between about 90° and about 180° around thecircumference of said cylindrical separator zone from the location ofsaid tangential introduction of said stream of pyrolysis products intosaid separator zone.
 18. The process as defined in claim 17, said streamof pyrolysis products being introduced tangentially through a tangentialinlet to said separator zone, said inlet extending substantially theentire length of said cylindrical separator zone, and said outletconduit being tangentially disposed with respect to said cylindricalseparator zone.
 19. The process as defined in claim 18, the length ofthe reduced rectangular cross section of said stream of pyrolysisproducts being substantially the length of said tangential inlet to saidcylindrical separator zone.
 20. The process as defined in claim 15, saidgases being removed from said separator zone through a perforate tubetherein.
 21. The process as defined in claim 15, said particulateprimary material being particulate coal and said particulate secondarymaterial being particulate char.
 22. The proces as defined in claim 19,said particulate primary material being particulate coal and saidparticulate secondary material being particulate char.
 23. Pyrolysisunit comprising means forming a rectangular slot for formation of a slotstream of a particulate primary material to be pyrolyzed, asubstantially rectangular pyrolysis reactor, said slot communicatingwith said reactor, means positioned on opposite sides of said reactorand in communication therewith, for introduction of particulatesecondary material as heat source, from said last mentioned means tosaid reactor for admixture therein with said slot stream of particulateprimary material, a substantially cylindrical separator, means forming atransition chamber from said reactor, said transition chamberterminating in a rectangular slot of smaller rectangular cross-sectionthan said rectangular reactor, a tangential inlet to said separator andin communication with said transition chamber, and a rectangular inletconduit communicating said last mentioned slot with said inlet to saidseparator, said last mentioned inlet being of the same length as saidlast mentioned slot, a solids outlet conduit positioned not more thanabout 180° around the circumference of said cylindrical separator fromsaid tangential inlet, and a perforate gas receiver mounted in saidseparator.
 24. Apparatus as defined in claim 23, said solids outletconduit being positioned about 90° around the circumference of saidcylindrical separator from said tangential inlet, said outlet conduithaving a wall at the upper end thereof communicating with saidseparator, whereby solids injected from said tangential inlet into saidseparator travel around one quarter of the circumference of saidseparator before impacting said wall of said outlet conduit for removaltherein.
 25. Apparatus as defined in claim 23, said cylindricalseparator being disposed with its axis in a horizontal position andhaving a length equal to the horizontal length of said reactor, of saidtransition chamber and of said rectangular inlet conduit.
 26. Apparatusas defined in claim 25, said solids outlet conduit being positionedabout 90° around the circumference of said cylindrical separator fromsaid tangential inlet, said outlet conduit having a wall at the upperend thereof communicating with said separator, whereby solids injectedfrom said tangential inlet into said separator travel around one quarterof the circumference of said separator before impacting said wall ofsaid outlet conduit for removal therein.
 27. Pyrolysis unit comprisingmeans forming a rectangular slot for formation of a slot stream of aparticulate primary material to be pyrolyzed, a substantiallyrectangular pyrolysis reactor, said slot communicating with saidreactor, means in communication with said reactor for introduction ofparticulate secondary material as heat source into said reactor foradmixture therein with said slot stream of particulate primary material,a substantially cylindrical separator for separating solids and gases,means forming a transition chamber from said reactor, said transitionchamber terminating in a rectangular slot, a tangential inlet to saidseparator and in communication with said rectangular slot in saidtransition chamber, and a solids outlet conduit from said separator andmeans for withdrawing gas from said separator.
 28. Pyrolysis unitcomprising means forming a rectangular slot for formation of a slotstream of a particulate primary material to be pyrolyzed, asubstantially rectangular pyrolysis reactor, said slot communicatingwith said reactor, means in communication with said reactor forintroduction of particulate secondary material as heat source into saidreactor for admixture therein with said slot stream of particulateprimary material, and substantially cylindrical separator means forseparating solids and gases, said separator means communicating withsaid reactor.
 29. Apparatus as defined in claim 28, including meansforming a transition chamber from said reactor, said transition chamberterminating in a rectangular slot, said separator means communicatingwith said last mentioned slot and said transition chamber.
 30. Apparatusas defined in claim 29, said transition chamber terminating in arectangular slot of smaller rectangular cross section than saidrectangular reactor, an inlet to said separator means, and a rectangularinlet conduit communicating said last mentioned slot with said inlet tosaid separator means, said last mentioned inlet being of the same lengthas said last mentioned slot.
 31. Apparatus as defined in claim 28, saidfirst mentioned means being a pair of rectangular wells positioned alongopposite sides of the upper portion of said reactor, said wells eachcomprising pipe means for introducing said particulate secondarymaterial to said well, a fluidizing chamber and means for introducing afluidizing gas into said fluidizing chamber, and means to permit thefluidized secondary material to overflow from each of said wells intothe upper portion of said reactor.
 32. Apparatus as defined in claim 31,said reactor having an upper wall portion terminating below the top ofsaid reactor, said last mentioned means comprising said upper wallportion and forming an overflow weir from each of said wells into saidpyrolysis reactor.
 33. A pyrolysis process which comprises passing ahigh velocity stream of a particulate primary material to be pyrolyzedthrough a rectangular slot to form a high velocity slot jet of saidparticulate material having a rectangular cross section. injecting saidslot jet into a substantially rectangular pyrolysis zone, introducing afluidized particulate secondary material as heat source into saidpyrolysis zone and mixing said particulate primary material and saidparticulate secondary material in said pyrolysis zone, and passing theresulting stream of said mixed particulate primary and secondarymaterials through said pyrolysis zone and pyrolyzing said mixturetherein, passing the resulting stream of pyrolysis products into asubstantially cylindrical separator zone, removing solids from saidseparator zone and removing gases from said separator zone.
 34. Theprocess as defined in claim 33, including passing said stream ofpyrolysis products through a chamber having a rectangular cross sectionwhich reduces in size in the direction of flow, prior to introducingsaid stream of pyrolysis products into said separator zone.
 35. Theprocess as defined in claim 33, wherein said fluidized particulatesecondary material overflows into said pyrolysis zone from wells on bothsides of said rectangular pyrolysis zone.
 36. The process as defined inclaim 33, said particulate primary material being particulate coal andsaid particulate secondary material being particulate char.